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05-17-2010, 12:13 PM #1
A single phase motor for a J-head?
I found this on, of course, the internet. Rather than all the jumping through hoops for VFD, RPC, etc. what about just installing a single phase motor on the Bridgeport mill?
Anyone out there ever try it?
Single Phase Conversion Kit for 1 HP Bridgeport Motor (NOT SHOWN)
05-17-2010, 12:49 PM #2
Looks to cost more and, with the pulley bore modification, to be more trouble than a basic VFD installation on a standard motor. Especially for the usual American Bridgeport having direct motor connections (instead of the UK / Euro style with a big services box on the side containing a husky transformer, NVR contactors for everything and mucho wiring).
Not enamoured of the taller motor. There are vibration issues on a Bridgeport head and a taller motor makes things worse.
Maybe a realistic option if your motor is kaput but not otherwise.
At current street / fleabay prices individual VFD is the only sensible option if you have only a couple of modest HP machines. All plug'n play which an economy (DIY) RPC rarely is.
05-17-2010, 02:24 PM #3
You give me the $500, and I could fly out to Washington and install a VFD for you.
05-17-2010, 08:29 PM #4
Do I have to feed you too?
My main dilemma is figuring out if the L200 unit I have will allow me to run the mill the way I run one back at the shop. At my age, I dislike having to run the same equipment two different ways. It's the old guy thing.
Still reading my book on the L200. Wish I was an electrical engineer. Too many TLA's in this book to keep track of... The more I read, the more it looks like I'll ebay off the L200 and get a RPC. That would allow me to run the mill via the mill's switch and not this potentiometer. I'll end up calling the company before I go another direction to get my questions and concerns answered. I'm getting answers 180 degrees different from different people on how the unit can be used.
Some lessons in life I try not to learn by brail.
05-17-2010, 08:52 PM #5
Don't be scared of manual. You only need about 3 pages of its info.
The stock switch can be wired to run VFD exactly like original, and a small pot added for the extra VFD option of speed control.
Best to just ask here how you want to run it, and we can walk you through wiring, programming, and install. There are a few people here on board in Seattle area that have done the installs before...
We will need to know exact VFD model number, motor nameplate info. Existing switch info, if it is to be reused.
The Bridgeport with a VFD is just so nice to run, compared to just on off reverse...
You can do it. Only low voltages on the control wiring, can't even get shocked.
The Motor input, VFD output, and Input, are the only High Voltage connections
05-18-2010, 03:17 AM #6
I presume your L200 is the Hitachi model so the standard parameters the unit was shipped with should be just fine for a basic motor installation like a Bridgeport. About the only thing I've ever bothered to fiddle with on a VFD has been the motor run up parameters (altho' sometime I have to grapple with end of feed stop switches on the Mitsubishi unit which runs my shaper). If it is the Hitachi unit then its compact enough to bolt onto the the machine. Either on the head or somewhere a little easier to reach. So bolt it on, connect the motor and a power in cable, drive it it off its own control panel and stop worrying about the geek stuff.
Set up a similar unit in that fashion on a J head fitted to an old round ram machine about 6 months back for a "less than intellectual" friend (a superb machinist but almost needs a minder for anything else!). He knows which buttons are forward / stop /backwards and to set the display between 30 and 70 and loves it. I did read the manual but the only bits I needed were the bolt hole layout and power in / out connections. Hardest bit was making the bracket.
05-18-2010, 05:43 AM #7
I like prime rib, but shrimp, lobster, and crab legs all make good appetizers.
I'd help with the settings, but I run an Emerson drive. The manuals on VFDs are crap! But once you figure out what's going on, they are a piece of cake to run. You can run through the stock BP switch, or put a simple on/off switch in the same place. There's little tricks on the parameters that you have to figure out. It took me 3 years to keep from hitting the brake when I hit the switch, but duct taping a cover over it stopped that.
This old guy would rather run VFDs any day over RPCs.
05-18-2010, 07:08 AM #8
Mebbie it's an Iowa thing...
But I'll second JR's note- if the whole VFD thing seems complicated, realize that once it's installed and set up, you have:
Forward - Stop - Reverse
That's one more 'control' than you had before.
Of course, you could leave the VFD set at one speed and change belts, if you enjoy it, but I"m running my BRJ on the middle-range, and just turning the knob for speed control.
In reality, the wiring connections are not complicated. The manuals, however, assume that whoever is setting it up, has a high knowledge-level of how 3 phase motors, and the VFD work.
What they SHOULD do (and for many reasons, they can't) is make a very, very simple 'idiot's guide' to hooking up each unit for a common machine, like a BRJ. I've been known to forget things, so for my own reference (after I did my first VFD), I made such a diagram for the Allen-Bradley 1305... and then I did one for the 1336S, and it's worked out well for me, and a few people that I've sent it out to. If you'd like to see an example, send me an email (they're just a wee bit too big 'a PDF to post here).
05-18-2010, 01:41 PM #9
Super Dave,I would appreciate seeing how you hooked up a VFD to your Bridgy.......'course I don't know if I can trust a guy that does such terrrrrrible things to poor lil ole Miller welders
05-18-2010, 09:59 PM #10
Well I FINALLY MADE it through that simple owners manual for the Hitachi L200 Series Inverter. So help me I though I was reading a script from Star Trek Next Generation where Data argues with "Q" about warp drives.
Having gone through this thing, I can say it does WAY MORE than what I'm after in a manual milling machine. It belongs in a 5 axis CNC mill, controlling speed and feed as different inside and outside areas are machined; not my old J-head.
I did reset the start / stop speeds for 1 sec. and not the 10 sec. defulat settings. Much better!
If, I can add a three postion switch for CW off ACW rotation I'll be a happy camper.
Looks like I'll keep it for a while and see how it goes. If I do scrap it out, I'm going straight to a single phase 1 1/2hp motor and skip the phase converters all together.
Thanks for all your tips guys. Even conflicting information helps narrow down the field of options.
Last edited by Gos; 05-19-2010 at 04:55 PM. Reason: Written tooooo late in the day.....